Certain crystalline materials may be manufactured or "grown" on a work piece or "substrate" under certain atmospheric and electromagnetic conditions. In particular, several materials of carbon and silicon may be grown on a wafer in the presence of ionized carbon or silicon, hydrogen, and a standing microwave. Such devices or "reactors" grow diamond, diamond-like carbon, and silicon carbide films.
Such films produced by chemical vapor deposition ("CVD") have many applications, from wear coatings and optical elements to electronic applications and packaging and as active components. For many of these applications, control of the film thickness, is important. Furthermore, uniformity of film thickness may be critical. For instance, thickness uniformity of approximately five percent is required of diamond films for use in x-ray lithography.
Currently, microwave plasma reactors are only able to produce films by CVD processes with thickness uniformities of 20 to 25 percent over a two inch diameter substrate.
Therefore a need has arisen for a method of producing uniform films in microwave plasma reactors.